Ophthalmic OpticsQuestion 2 of 100
A lens has a focal length of 25 cm. What is its dioptric power?
a.+2.00 D
b.+4.00 D
c.+0.25 D
d.+25.00 D
Explanation
Power equals 1 divided by focal length in meters. 25 cm = 0.25 m, so 1 / 0.25 = +4.00 D. Focal length and power are reciprocals of one another.
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